Classes of Levers: Simple Machines

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Questions and Answers

In a lever system, what distinguishes one class of lever from another?

The position of the force, load, and fulcrum relative to each other. (correct)
The type of materials used to construct the lever.
The amount of force applied.
The size and weight of the load being moved.

Using the FLE mnemonic, if 'L' is in the middle, which class of lever are you considering?

First class lever
Third class lever
Second class lever (correct)
Fourth class lever

Scissors are an example of which class of lever, and why?

Second class, because the load is between the force and the fulcrum.
Third class, because the force is between the fulcrum and the load.
Second class, because the fulcrum is at one end.
First class, because the fulcrum is between the force and the load. (correct)

In a third class lever, which of the following is always true?

The force is in the middle, between the fulcrum and the load. (B) Signup and view all the answers

A wheelbarrow is an example of which class of lever? Which component is located between the other two?

Second class lever; the load. (A) Signup and view all the answers

If a lever has the force applied between the fulcrum and the load, which class does it belong to, and which part of the FLE mnemonic would help you remember this?

Third class; the 'E' in FLE (C) Signup and view all the answers

Which of the following tools operates using the principle of a second-class lever?

Stapler (B) Signup and view all the answers

A person using a rake to gather leaves is using which class of lever? Where is the effort applied?

Third class; near the middle of the rake. (D) Signup and view all the answers

How might understanding the classes of levers help in designing a new tool?

It allows for optimizing the force required based on lever arrangement. (C) Signup and view all the answers

Which of the following best illustrates a first-class lever system?

A pair of pliers cutting a wire. (B) Signup and view all the answers

Flashcards

What are levers?

Simple machines using force, load, and a fulcrum.

What is a fulcrum?

The balance point in a lever system.

What defines a first class lever?

Fulcrum is between force and load.

What defines a second class lever?

Load is between the fulcrum and the force.

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What defines a third class lever?

Effort (force) is between the fulcrum and the load.

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What is FLE?

Acronym to remember lever classes

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Study Notes

Classes of Levers

Levers are simple machines and the basis of many tools
Levers are found in the human body
A force applied at one point moves a load at another point through a balance point called the fulcrum
The position of the force, load, and fulcrum distinguishes the class of lever
There are three classes of levers: first, second, and third

First Class Levers

The fulcrum is in the middle
The force is on one side and the load is on the opposite end
Examples include a seesaw, scissors (force, fulcrum, and load), and pliers

Second Class Levers

The load is between the force and the fulcrum
Examples include a wheelbarrow (force, fulcrum, and load), a nutcracker, and a stapler

Third Class Levers

The fulcrum is on one end, the force is in the middle, and the load is on the other end
Examples include a hockey stick, a rake, and a hammer (fulcrum, force, and load)